Surface effect craft

ABSTRACT

A surface effect craft of simple construction achieving improved operational stability and performance at various speeds. The craft includes a continuous aerodynamic wing structure having maximum thickness ratio wing thickness to chord length on the order of 30%. The outer wing sections are swept back forming a generally U-shaped rear section. The center of the craft preferably has a generally horizontal bottom forming a hydrodynamic planing surface having longitudinal concavities positioned on an underside thereof. The mass distribution of the craft is designed with an engine in the front and ducted fan propulsion system to the rear of the pilot&#39;s central seating position. This arrangement permits the pilot to utilize body movement to control the attitude of the watercraft during operation.

RELATED U.S. APPLICATION DATA

This is a continuation-in-part of Ser. No. 07/540,887 filed Jun. 20,1990, now U.S. Pat. No. 5,357,894 which is a continuation of Ser. No.07/334,760 filed Apr. 6, 1989, abandoned, which is a continuation ofSer. No. 06/856,674 filed Apr. 25, 1986, abandoned.

FIELD OF THE INVENTION

The field of the present invention relates to flying crafts and towatercrafts and in particular to a watercraft having an aerodynamicconfiguration having improved stability and performance especially attransitional (transitioning from water to air travel) and at higherspeeds. In its preferred configuration, the craft may employ groundeffect for aerodynamic performance in proximity to the surface.

BACKGROUND OF THE INVENTION

For many years, designers of pleasure crafts have been researchingwater-borne craft designs which have aerodynamic elements generatinglift force on the craft structure when at speed to assist raising thecraft above its at rest buoyant draft. It is desirable to reduce viscousdrag on the craft hull for providing increased speed and/or efficiencyover a craft with a conventional design having the same weight andpower. Early designs effectuating this objective are evidenced by thehydroplane style boat which comprises a pair of structurally supportedsponsons separated by a raised hull floor, which form an underlyingtunnel through which air is flowed. The underflowing airstream may alsoprovide a lift force through the force of the airstream against the hullfloor or through compression of the entering air mass between the watersurface and the hull floor of the boat, or both.

The hull of a hydroplane is supported by buoyant force generally alongits entire underside, including the hull floor and sponsons, when atrest. Under power, the hydroplane boat is substantially supported byhydrodynamic force acting against the outwardly and forwardly positionedsponsons, and by radial thrust from the prop extending from the rear ofthe hull. This triangular footing provides reasonable stability insmooth surfaced water; however, the wide beam of the sponsons andairflow through the centrally defined tunnel can experience decreasedstability, particularly in rough surface conditions.

Generally, hydroplane style boats are designed with the cockpit inopposition to the powerplant, i.e. the cockpit is in the front if theengine is in the rear and vice versa, for heavier designs. For lighterdesigns, for instance boats under fifteen feet in length, the cockpit isgenerally positioned in the stern so that the pilot is within reach ofan outboard type motor mounted to the transom of the boat.

Tri-hull boat designs, exemplified for instance in U.S. Pat. No.3,952,678, have been described as improvements over the basic hydroplanestyle hull. Such boat designs comprise a third water borne hullgenerally positioned centrally between the sponsons to assist in dynamicstability. The depths of the hull and sponsons are generally equal, asshown, to provide a uniform and broad base support for the hull in thewater, with their underlying surfaces being flat and horizontallydisposed.

The third central hull is thought to provide additional stability inrough surface conditions or high wind conditions which may create anunstable situation for a hydroplane style boat. Additionally, aforwardly rising support structure for the sponsons is described whichprovides an upwardly and forwardly angled undersurface which is boundedby the central hull and the respective sponsons. This undersurface isused to compress an airstream received when the boat is in motion toprovide aerodynamic lift force on the underside of the structure inaddition to the hydrodynamic lift force generated on the hull when theboat is under power. The boat described in the U.S. Pat. No. 3,952,678appears to be larger than 20 feet in length and has the cockpitpositioned rearwardly with the engine placed in an opposing forwardposition.

Another differing style craft which is substantially aerodynamic indesign while utilizing both aerodynamic and hydrodynamic lift forcesduring the transitional period from standstill through surfacedeparture, is described in U.S. Pat. No. 3,190,582 and related patentnumbers 3,627,235 and 3,830,448. The aircraft disclosed therein is, atrest, supported on forwardly and outwardly extended sponsons joined to acentral craft fuselage. The sponsons are joined to the fuselage byairfoil shaped structures or wings extending outwardly and downwardly tothe sponsons from the fuselage to provide a reverse dihedral wingconfiguration. This design positions forward portions of the fuselageabove the sponsons such that the forward portion of the fuselage cannotcontact the surface of the water on which the craft is supported. Thewing structures extend rearwardly from the outwardly and downwardlydirected leading edge which extends substantially perpendicular with thelongitudinal axis of the fuselage, to an inwardly swept back rearwardedge converging at the tail of the fuselage. This wing configurationprovides a triangular shaped frontal opening from the nose of thefuselage to the interior side of each respective sponson to define anunderlying space below the fuselage and wing structures which is closedat the rearward edge of the wing against the surface of the water. Therearward edge of the wing is generally at the same vertical height asthe sponsons and when at rest meets the water surface from the sponsonto the rear of the fuselage. Thus at rest the craft rests on thesponsons and the rearward edge of the wing and the rearward end of thefuselage, all of which are in contact with the water to support theaircraft.

When the aircraft begins operation and accelerates, the air flow intothe triangular shaped frontal opening of the wing begins to build airpressure under the aircraft, between the undersurface of the wings andfuselage and the surface of the water. Maximum aerodynamic pressurebuilds at the rearward edge of the wings so that the rear of theaircraft lifts from the surface of the water first and the aircraft issupported by hydrodynamic pressure on the sponsons and the aerodynamicpressure along the rearward edge of the wings.

Operation of the aircraft as velocity increases becomes increasinglyunstable however due to loss of aerodynamic lift as the rear edges ofthe wings rise and the ram air and ground effects lift dissipateresulting in difficulty in pitch or attitude control of the aircraft.Due to the reverse dihedral configuration of the wings, roll of thecraft in one direction or the other tends to increase rotation in thesame direction. This increased rotation is caused by increased lift onthe rising (more horizontal) wing as compared to the other, a phenomenawhich additionally causes attitude and roll instability. Forwardly andoutwardly positioned wing tips floats may impact the water and if onlyone wing tip impacts the water may cause the craft to cartwheel withundesirable results.

If the aircraft is piloted through the transitional period, the aircraftattains a stable and substantially horizontal pitch attitude and airflowover the wings generates aerodynamic lift to raise the craft from thewater surface into free flight.

The aircraft fuselage is configured in a common design having thecockpit positioned as far forward as is practical in view of other majorcomponents contained in the fuselage, such as engine, avionics, etc.which are positioned in the nose structure of the craft.

A watercraft comprising a singular water borne hull which additionallyutilizes a wing(s) for stability and control in operation is known as aSki Plane® which is manufactured by a concern known as Ski-Plane, Inc.of Newport Beach, Calif. The hull of the Ski Plane® is a narrowcigar-shaped structure which has a primary substantially flat and narrowundersurface extending the length of the hull. A pair of secondary andadjacent horizontal undersurface are disposed on either side and arepart of the hull, beginning with a raised surface portion approximately1/3 along the length of the hull from the front and curved downwardlyand rearwardly to a flat undersurface contiguous with the primaryundersurface approximately midway along the length of the hull. Thesecondary undersurface generally provided to aid high speed stabilitywhile decreasing the area of undersurface in contact with the water toreduce viscous drag.

A pair of wing structures extend laterally from the rear of the craftand exhibit a slight dihedral angle with the hull. Each wing structureends with a downwardly curved portion or "dropping edge" which acts torestrict lateral flow of air from beneath the wing to improve stallcharacteristics, i.e. reduce the speed at which stall occurs. Aileronsextend along the rearward edge of each wing structure to assist inrotational control of the craft when at speed. A fixed laterallyextending winglet is also provided at the nose of the craft.

The Ski Plane® is powered by a typical outboard motor mounted to thetransom of the hull to propel the craft and generate primary rotationalcontrol through a driving propeller disposed below the surface of thewater. A pair of cockpits are provided in a generally forward positionof the hull. Major control, fuel and drive components are mounted withinthe stern in the area where the wing structures are attached.

All of these crafts have limitations in stability, efficiency and/orperformance. A watercraft design having superior stability, efficiencyor performance would therefore be desirable.

SUMMARY OF THE INVENTION

The present invention is directed to a watercraft having a central hulland first and second wing sections. In a preferred embodiment, the firstand second wing sections merge into the central hull to form acontinuous wing structure. The wing structures are very thick withmaximum thickness ratio of wing thickness to chord length on the orderof 30% with the first and second wing sections being swept back, thewing shaped structure forming a generally U-shaped rear section (as bestviewed from a rear plan or sectional view).

In a second embodiment, the watercraft includes a pair of laterallydisposed sponsons which are mounted to the hull through support of wingstructures. The watercraft design positions the pair of sponsonsequidistantly and laterally from the watercraft central hull, andrearwardly from the bow. The wing structures have an aerodynamicallyconfigured shape to generate lift force to improve transitional and highspeed performance of the watercraft. Preferably, the wing structuresmounting the sponsons to the hull are configured to have the shape of anairfoil with a relatively large radius leading edge to improve low speedlift and stall characteristics. Also, the wing structures extendupwardly and outwardly from the central hull to define a dihedral anglewith a horizontal plane of the craft to provide roll stability. Theinside surface of each sponson provides a barrier which prevents lateralflow of air from under each of the respective wing structures to furtherreduce stall airspeed, and to permit efficient utilization of the forcesgenerated beneath the wing structures from the force of airflow.

Preferably, the central hull has a concave shaped undersurface whichextends from the bow rearwardly underneath the craft to the stern toimprove hydrodynamic lift. Each of the sponsons (if any) also has aconcave shaped surface or inwardly formed scallop along its undersurfaceto improve performance and assist in obtaining directional stability ofthe watercraft. Preferably the concave undersurface of each sponson isdirected slightly outwardly and downwardly from the center of the craft.

Preferably, the watercraft is designed to have a mass distribution whichenables a pilot to control the attitude of the watercraft through thecontrol mechanisms and by the positioning of the pilot's body within acockpit contained in a central hull. A cockpit is formed along thelongitudinal axis of the central hull preferably forward of the midposition to provide a seating position for a pilot. The massdistribution of the craft is designed such that the center of gravity ofthe craft lies within a longitudinal range beneath a seating positionfor a pilot in the cockpit. This permits the pilot to utilize bodymovement to control the attitude of the watercraft when in operation.The mass elements of the craft are distributed in the central hull toplace the center of gravity within the defined longitudinal range belowthe seating position of the pilot. In a preferred configuration, thepower plant is positioned in the nose or bow of the watercraft and thepropulsion system is positioned in the stern. Drive means are providedextending below the seating position of the pilot to transfer power fromthe powerplant to the propulsion system. Fuel storage is preferablypositioned immediately below the seating position of the pilot withinthe longitudinal range of the center of gravity so that fuel usage willnot substantially disturb the mass distribution of the watercraft.

The propulsion system is preferably a ducted fan positioned in the sternof the watercraft with an air intake immediately behind the seatingposition of the pilot in the cockpit. The ducted fan preferably includestorque control means to eliminate torque forces characteristic of thefan from acting on the watercraft. A rudder may be provided behind theoutlet of the ducted fan to provide turning and yaw control. Additionalcontrol surfaces may be provided to obtain roll and pitch control.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a downwardly directed left side perspective view of apreferred watercraft according to the present invention;

FIG. 2 is an upwardly directed right side perspective view of thewatercraft of FIG. 1;

FIG. 3 is a front plan view of the watercraft of FIG. 1 showing thelateral configuration of the support structures for the sponsons;

FIG. 4 is a section view through the longitudinal axis of the watercraftdisplaying the mass elements contained within the central hull in fullview and a seating position for pilot with the pilot's body indicatedwith a broken line.

FIG. 5 is a cross sectional view of the watercraft of FIG. 3 taken alongline 5--5 showing the aerodynamic shape of the wing structure;

FIG. 6 is a side view in partial cross section of an alternatewatercraft embodiment according to the present invention;

FIG. 7 is a top plan view of the watercraft of FIG. 6;

FIG. 8 is a side view of the watercraft of FIG. 7 diagrammaticallyillustrating the wing shape cross sections A--A through F--F of FIG. 7;

FIG. 9 is a bottom plan view of the watercraft of FIG. 6;

FIG. 10 is rear elevation view of the watercraft of FIG. 6;

FIG. 11 is a front elevation view of the watercraft as in FIG. 10 withthe winglets in a retracted position;

FIG. 12 is a diagrammatic drawing of wing shape showing a chordline;

FIG. 13 is a diagrammatic drawing of the wing shape of FIG. 12 showing ameanline;

FIG. 14 is diagrammatic drawing of a wing shape according to a preferredembodiment of the present application in normal attitude showing theupwardly curved meanline;

FIG. 15 is a diagrammatic drawing of the wing shape of FIG. 14 showingair flow thereacross in normal operating condition;

FIG. 16 is a diagrammatic drawing of the wing shape of FIG. 14 in adownwardly pitched condition showing air flow thereacross;

FIG. 17 is a diagrammatic drawing of a conventional wing shape showingair flow thereacross in a pitched up condition;

FIG. 18 is a top left side perspective view of another alternatewatercraft embodiment according to the present invention;

FIG. 19 is a rear left side perspective view of the watercraft of FIG.18;

FIG. 20 is a side view in partial cross section of an the watercraft ofFIG. 18;

FIG. 21 is a top plan view of the watercraft of FIG. 18;

FIG. 22 is a cross sectional side view of FIG. 21 diagrammaticallyillustrating the wing shape cross sections A--A through F--F;

FIG. 23 is a bottom plan view of the watercraft of FIG. 18;

FIG. 24 is a rear elevation view of the watercraft of FIG. 18;

FIG. 25 is a front elevation view of the alternate watercraft;

FIG. 26 is a rear elevation view of the watercraft of FIG. 25;

FIG. 27 is a top left side perspective view of craft incorporating thepreferred wing design and body shape of the embodiments of FIGS. 18-26into a commercial-size vehicle;

FIG. 28 is a top left side perspective view of craft incorporating thepreferred wing design and body shape of the embodiments of FIGS. 18-26and including a separate wing and tail assembly;

FIG. 29 is a front elevation view of the craft of FIG. 28; and

FIG. 30 is a left side elevation view of the craft of FIG. 28.

PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

Preferred embodiments of the present application will now be describedwith respect to the drawings. To facilitate description, any numeralrepresenting an element in one figure will represent the same element inany other figure.

An embodiment for a first preferred watercraft 5 is shown in FIGS. 1-3.The watercraft 5 comprises a central hull 10 forming a central portionof the craft. A pair of laterally disposed sponsons 12 and 14,respectively, are positioned in parallel relationship with thelongitudinal axis of the hull and are mounted to the central hull 10 byoutwardly directed support or wing structures 16 and 18, respectively.The sponsons 12 and 14 are preferably aligned rearwardly of the bow ofthe central hull 10.

The wing structures 16 and 18 are identical in structure andconfiguration though of mirror image and will be describedsimultaneously with this understanding. The wing structures 16, 18mounting their respective sponson 12, 14 extend from the side of thecentral hull 10 laterally to the sponson. The wing structures 16, 18have undersurfaces 20, 22, each of which is outwardly and upwardlydirected to form a dihedral angle with a horizontal plane through thecentral hull 10 as it reaches out to its respective sponson 12, 14.Preferably the wing section 16, 18 is formed with a positive dihedralangle (for example about 3°). Each of the undersurfaces 20, 22 has acurved section 17, 19 to blend with the side surfaces of the centralhull 10. At their outer ends, the undersurfaces 20, 22 have outwardlyand downwardly curved sections 21, 23 each of which form a "droppingedge" bounding the undersurfaces 20, 22 of the wing section 16, 18 andblending into the interior side walls of each of the respective sponsons12, 14. The upper side of each of the wing structures 16, 18 extendsoutwardly and curve downwardly to blend into each of the outer surfacesof the sponsons 12, 14 which they support. This wing structure designforms a smooth and continuous form for the upper and under surfaceswhich smoothly form into the supported sponsons 12, 14.

Each of the wing structures 16, 18 has an aerodynamically configuredshape, i.e., has the shape of an airfoil. This aerodynamic shape may beclearly seen in the cross sectional view of FIG. 5 taken along line 5--5of FIG. 3 through the wing structure 16 to show the curved upper surface25 extending from the front to the rear of the wing section and thesubstantially flat undersurface 20, extending from the front to the rearof the wing section.

Referring again to FIGS. 1-3, the leading edge of each wing section 16and 18 extends outwardly and rearwardly from the bow of the central hull10 to the front of the rearwardly positioned sponsons 12, 14,respectively which they support. Each of the sponsons 12 and 14 ispositioned parallel with the longitudinal axis of the central hull 10,beginning rearwardly of the bow of the central hull 10 and ending at apoint substantially flush with the stern of the central hull 10. Theleading edge of the wing section 16, 18 thus form a sweptback wingconfiguration from the bow of the central hull 10. Preferably, theleading edges 36, 38 of the wing section 16, 18, respectively, extendrearwardly forming a 60° angle with the longitudinal axis of the centralhull 10. The leading edges 36 and 38 have a relatively large radiusfrontal surface, such as is shown in the cross section depicted in FIG.5 for leading edge 36. The trailing edges 40 and 42 of the wingstructures 16 and 18, respectively, are generally narrow in width andextend perpendicularly to the rearward end of each sponson 12 and 14 toform a straight trailing edge.

In preferred form, the central hull 10 has a concavity 24 inwardlyformed along the length of the hull's undersurface. The concavity 24rises forwardly and upwardly into the lower portions of the bow of thecentral hull 10 to form a forwardly directed concave surface at thefrontal portion of the bow bounded by edges 24a and 24b respectively.

Similarly, each of the sponsons 12, 14 has a concave shaped undersurface13 and 15, respectively, formed along its length with a forwardly andupwardly curved portion to form a forwardly directed, concave frontalsurface. Preferably, the concavities 13 and 15 formed into sponsons 12and 14, respectively, are slightly inwardly directed and preferablysymmetrical about a plane forming an angle between 20° and 30° with thevertical.

A cockpit 28 is formed in the upper surface of the central hull 10 andis positioned approximately 1/3 along the longitudinal length of thecentral hull from the bow to the rear. The cockpit 28 contains a seatingposition 30 for a pilot and also contains control elements, as forexample steering handle 40. The upper surface of the bow of the centralhull 10 is shown with an air inlet 45 formed to provide an airstream toradiator means 43 for cooling a power plant used to drive the watercraft5.

A ducted fan 32 is positioned rearwardly of the cockpit 28 to providemotive force for propelling the watercraft. A rudder 34 is positionedbehind the outlet 65 of the ducted fan 32 to direct the airflow from theducted fan to provide directional control for the watercraft. The ductedfan 32 has an inlet 59 behind the cockpit 28 to receive air which isthen compressed by the rotating fan blade 62 to force compressed air athigh speed out of the ducted fan outlet 65. Horizontal airflow controlelements may also be provided.

The mass distribution of the watercraft is designed so that the centerof gravity of the craft lies within a longitudinal range along thelongitudinal axis of the central hull 10, shown in FIG. 4 as bounded byfront plane P₁ and rear plane p₂ extending perpendicularly with thelongitudinal axis of the craft. The seating position 30 of the pilotwithin the cockpit 28 of the central hull 10 is positioned substantiallybetween the planes P₁ and p₂ thus positioning the driver 29substantially within the range of the center of gravity of the craft 5.Preferably, the position of the center of gravity is below the seatingposition 30 of the pilot 29 so that the pilot is seated over the centerof gravity.

The mass elements mounted within central hull 10 are distributed withinthe hull to place the center of gravity within the defined longitudinalrange between planes P₁ and p₂ and below the seating position of thepilot. The fuel tank 31 is positioned below the seating position 30 ofthe pilot 29 to provide fuel storage within the range of the center ofgravity between planes P₁ and p₂ so that fuel usage will notsubstantially affect the balance of the craft. A power plant 44 ispositioned forwardly of the cockpit 28 in the bow of the craft and lowerthan the seating position 30 of the pilot 29. The power plant 44 may bea typical multi-cylinder 2-cycle marine engine such as is commonly knownby those in the art. The engine 44 may include a radiator 43 positionedadjacent the air inlet 45. The ducted fan 32 is positioned in the sternof the craft and is mounted to direct the thrust from the airflow whichit generates over the surface of the water on which the craft issupported. The ducted fan 32 generally comprises a hub 60 which mounts aplurality of fan blades 62 radially around the hub 60. The fan blades 62are bounded by a cylindrical wall or fan duct 63. A faring 66 extendsrearwardly from the hub 60 to provide a smooth surface over which theairflow compressed by the fan blades 62 may pass. A torque control meansto correct torque forces generated by thrust of the ducted fan 32 isprovided, such as curved vanes 64 which slightly redirect the flow ofair leaving the fan blades 62 as they are powered. The flow of airleaving the ducted fan passes by the rudder 34 for directional control.

Power from the power plant 44 is transmitted to rotate the ducted fan 32through drive means comprising a first horizontally disposed shaft 46extending below the seating position 30 of the driver. The shaft ismounted for rotation by suitable bearing support means such as theengine 44 and a bearing support 47. At the rearward end of the shaft 46a pulley 48 is mounted to drive a fan shaft 54 through pulley 50 mountedon such shaft 54 with a belt 52 interconnecting the pulleys 48 and 50.The fan shaft 54 may support the ducted fan hub 60 and is mounted forrotation by suitable bearing support means (not shown). The power plant44 the drive means comprising the shafts 46, 54 with the belt drive andthe ducted fan 32 are all elements commonly known to those skilled inthe art and can be selected from any one of a number of manufactures.The power plant 44, the drive means and the ducted fan 32 are mountedwithin the hull 10 such that in combination with the mass of the hull,their individual masses combine to position the center of gravity forthe watercraft within the longitudinal range between the planes P₁ andp₂ so that the seating position of the driver 30 is positioned above thecenter of gravity.

Control means (not shown) may be provided for controlling the speed ofthe engine 44 and for controlling the rudder 34 such as through controlhandle 40 which communicates with the rudder 34 through a controllinkage 41.

The watercraft, including the central hull 10, the wing section 16 and18 and the sponsons 12 and 14, is preferably constructed in a one-piecestructure from a structurally molded foam composition having a toughouter surface for durability. However, other materials which aresufficiently light while rigid may be used such as fiberglass or otherplastics or laminations as would be selected by one skilled in the artof watercraft hull design.

In operation as the watercraft accelerates hydrodynamic forces exertedagainst the forward portion of the central hull and against the sponsonspitch the craft upwardly. This raises the swept back leading edge of thewing sections supporting the sponsons to enlarge the frontal windowbetween the undersurface of the wing sections and the surface of thewater, while lowering the trailing edge of the wing sections close to oron the surface of the water to substantially close the passage for airat the trailing edge of each wing section. This forms an air pocketbelow each wing section which receives the airstream as the watercrafturges ahead to generate ram and ground effect lift on the under surfaceof each wing section. The center of aerodynamic lift on the wing sectionis rearwardly positioned.

As the watercraft increases in speed and begins to plane on the surfaceof the water, the center of hydrodynamic lift moves rearwardly along theundersurface of the hull permitting the watercraft to decrease itsupwardly pitched attitude and become more horizontally disposed.Aerodynamic lift at the rearward portions of the wing sections assist indecreasing the upward pitch of the craft. As the watercraft nosesforward and the upward pitch decreases not only does the center ofhydrodynamic lift move rearward on the undersurface of the hull butairflow is permitted over the wing sections as the trailing edge of eachwing section lifts from the surface of the water. This generatesaerodynamic lift force on the wing sections. The center of aerodynamicand/or ground effect forces generated on each of the wing sections moveforwardly.

As the watercraft goes through transition and approaches operationalspeed the center of hydrodynamic and/or ground effect lift force on eachof the wing sections converges longitudinally, i.e. the center ofhydrodynamic force moves toward the rear of the craft and the center ofaerodynamic and/or ground effect force moves toward the front of thecraft, such that the summation of forces enters into the longitudinalrange of the center of gravity of the craft. In other words viewing thelongitudinal range of the center of gravity as bounded on a forward sideby a first plane orthogonal along the longitudinal axis of the craft andbounded on the rearward side by a second plane orthogonal to said axis,the summed hydrodynamic and aerodynamic and/or ground effect forces willconverge within the two bounding planes. Thus, when the watercraft is atspeed not only is the center of gravity, which is the balance point ofthe craft, positioned within the defined longitudinal range, but thelift forces acting on the craft are also positioned within this range toprovide the pilot attitude control of the watercraft by shifting hisweight with respect thereto. Attitude control is thus assisted by apilot shifting body position in the cockpit, or leaning in a desireddirection. This control is possible because the longitudinal rangebounding the center of gravity and lift forces is substantially withinthe seating position of the pilot in the craft and preferably with thefuel supply included so that the balance of forces is not substantiallyupset by fuel usage. The pilot may thus shift his weight forward to nosethe craft downwardly and shift his weight aft to nose the craftupwardly. Additionally, since the center of gravity is positioneddirectly under the pilot, the pilot may lean to the left or right torotate the craft to the left or right, respectively. The watercraft maythus be controlled by the pilot through usage of the control elements ofthe watercraft, especially the rudder and/or horizontal stabilizers, andthrough shifting of body weight as is easily accomplished within thecockpit when the craft is in operation.

FIGS. 6-11 illustrate an alternative embodiment of a watercraft 100having a pontoonless single form body structure 110. The body structure110 has left and right wing sections 140, 150 which merge together toform a continuous central hull section 120. The watercraft 100 isconstructed such that its mass elements, which include the engine 160,drive train 174 and propulsion mechanism (shown as a ducted fan 180),are distributed to place the center of gravity (C/G) of the craft,without the presence of any pilot or riders, within the vehicle'selongated bench seating area 175. In a preferred configuration, thecraft's center of gravity is located generally centrally beneath theseating position of the pilot 105.

The desired balance of the craft 100 (to control pitching moment) isachieved by locating the engine 160 forward of the elongated benchseating area 175, which is long enough to permit movement of theoperator/operators forward and rearward. The desired balance may beenhanced by locating the ducted fan 180 rearward of the elongatedseating area 175. The craft 100 may be constructed with an inherentstability which permits the pilot 105 to alter the pitch of the craft bymoving body position forward or rearward. The pilot 105 straddles theseating area 175 with the pilot's feet being permitted to comfortablyrest on the bottom of the craft 100. The pilot steers the craft 100 byleaning to one side or the other in addition to turning the steeringbars 171 which operate the rear rudder 198. Though details of theconnection are not shown, the steering bars 171 are operably connectedto the rudder by a suitable drive mechanism such as steering cables.

The engine 160 may comprise a typical internal combustion marine engine,but other power plants designs may be employed. For improved airflow andcooling, the radiator 165 for the engine 160 may be located to the rearof the craft 100.

To prevent fuel consumption from substantially disturbing massdistribution, the craft 100 includes means for minimizing disturbance ofmass distribution due to fuel consumption by positioning the fuelstorage tank 177 beneath the seating position 175. Therefore, as thefuel in the tank 177 is consumed, the weight of fuel remains balancedabout the C/G.

The output of the engine 160 is transmitted through a transmission 172(which alternately may comprise a clutch or torque converter) and thentransmitted via the drive train 174 to the ducted fan 180. Thethrustline T_(n) is such that its output acts in a straight line to thecenter of gravity such that no pitch moments (or a minimum amount ofpitch moment) is applied to the craft due to the thrust applied by theducted fan 180. Moreover, the thrust line T_(L) is parallel to thehydrodynamic surface, i.e., the flat bottom surface of the craft. Thedrive train 174 passes beneath the seating area 175 and is actuallystraddled by the legs of the pilot 105 (as well as by any passenger).The ducted fan 180 is protected from water damage by its dry location.

FIGS. 10-11 illustrate the craft 100 constructed with collapsible wingsections 142, 152. The wing sections 142, 152 are generally fixed inplace to the central hull portion 120. Upon release, the left wingsection 142 may be pivoted above the central hull section 120, the leftwing section 142 being mounted to pivotable support arms 144, 146.Similarly, the right wing section 152 may be pivoted above the centralhull section 120, it being mounted to pivotable support arms 154, 156.In this collapsed condition, the craft 100 may be more readilytransported (because of its reduced width such as by trailer) or stored.

The craft 100 possesses a unique wing shape. As described above, thecraft 100 has wing sections 140, 150 which blend together with thecentral hull section 120 to form a single, continuous flying bodystructure 110. The entire body structure 110 (i.e. the wing sections140, 150 and central hull section 120) is wing-shaped and provides liftfor the craft. Such a design is unlike other crafts such as flying boatsor seaplanes with pontoons in which the central hull providesessentially no lift.

Details of the wing shape are illustrated in FIGS. 7-8. FIG. 7 hascross-section lines A--A through F--F which refer to corresponding linesA through F in FIG. 8, illustrating the cross-sectional wing shape atthe particular cross-sectional location. As shown in the figures, theleading edge of the body structure is extremely thick with asubstantially horizontal, flat hydrodynamic bottom (the planing surface)and a substantially built-in angle of attack relative to the flat bottomplaning surface. The wing shape has a maximum % thickness (ratio of wingthickness to chord length) on the order of 30% which is about twice (ormore) that of typical wing designs. As shown in the cross-section linesA through F in FIG. 8, the maximum % thickness remains approximatelyconstant throughout the wing span of the craft 100. The thick wingenables the thrust forces to act directly on the center of gravity aswell as enabling the thrust forces to act parallel to the planingsurface. This thick wing design may also be useful for conventionalaviation.

The bottom surface is flat to accommodate aquatic planing. In addition,the bottom surface is equipped with hydrodynamic stabilizers 190comprising a series of longitudinal concavities 192, 193, 194, 195positioned on the underside of the central hull section 120. It isintended that these concavities 192-195 provide lateral hydrodynamicstability and increased lift. The concavities 192-195 are preferablylongitudinally aligned and provide lateral resistance when turningduring water operation, otherwise the craft would tend to continue tomove along a straight line in a crabbing manner when the pilot desiresto execute a turn. The stabilizers 190 are formed with a step 191 suchthat the forward portion of the bottom surface of the craft 100 is lowerthan the rear surface.

The present inventor has determined that the preferred planform (asviewed from a simplified top plan view) for directional stability of acraft requiring no vertical stabilizers was a half-circle leading edge(with the radius at the C/G) with a rectangle with its width sharing thediameter of the half circle with an area three times that of the halfcircle and the center of lift C/L located at 25% of the symmetricalcross sectional area. Such a craft has a relatively low aspect ratio(AR=wingspan/average chord length) which for the above configuration ison the order of 0.6 as compared to other craft having aspect ratios ofseveral times higher. The preferred aspect ratio is less than 1.0. Finsmay be required for a narrower swept planform such as one for a craft asshown in FIGS. 6-9 or FIGS. 21-24 which is trailerable [maximum 8 ft(2.5 m) in width]. In a large freighter application such as illustratedin FIG. 27, a greatly reduced or finless design without empennage orsponsons may be practicable.

This planform enables the center of gravity and the center of lift to bereadily placed in the same location. Moreover, this configuration ispreferred because it has a configuration with a narrow lateral dimensionand a long longitudinal dimension (i.e., low aspect ratio) resulting ingreater safety in operation. A vehicle having a higher aspect ratio orwith sponson at forward and lateral locations is more susceptible toundesirable impacts with waves. That is, if one wing side impacts a wavewhile the other does not, a cartwheel effect may be introduced. Thelonger length craft is also more apt to bridge the gap betweensuccessive waves and with its low aspect ratio, it is less likely thatthe wing portion on one side of the craft may stall and impact a wavewithout the wing portion on the other side also impacting.

Unlike conventional watercraft, the craft 100 is aerodynamic and, atspeed uses ground effect to ride above the water surface. Even if a waveis occasionally impacted, the craft will still remain primarilysupported by air in flight, thereby minimizing the severity of any waterimpact resulting in a "soft ride" for the vehicle. The softnessincreases with speed by which the craft gains altitude over the waves.This soft ride is not experienced by conventional watercraft, flyingboats, and sea planes.

Another alternative embodiment of a preferred wing design will now bedescribed. To assist in describing the preferred wing shapes, certainterminology will be defined. The chordline of a wing is defined as astraight line drawn from the leading edge to the trailing edge of thewing. It is possible that the chordline may pass outside of the wingsurface. The meanline of the wing is defined as a line connecting all ofthe points midway between the upper wing surface and the lower wingsurface. The meanline is also referred to as the midline or the meancamber line. Being between the upper and lower wing surfaces, themeanline cannot pass outside the wing surface. The perpendiculardistance between the chordline and the meanline is called camber, withmaximum camber being the camber at which this distance is greatest. Thethickness of a wing is the distance between the upper surface and thelower surface. Chord length is the length of the chordline.

FIG. 12 is a cross section of a thick wing 210 (its maximum thicknessbeing about 23% of chord length) with a chordline 212 extending from theleading edge 214 to the trailing edge 216. Following more conventionalwing shape theory, the wing 210 has a configuration with more wing areaabove the chordline 212 than below. FIG. 13 illustrates the same wingshape 210 with a meanline 218 drawn. As shown in the figure, themeanline is convex in shape, curving downward as the meanline approachesthe leading edge 214 of the wing 210. The wing 210 tends to follow thecurve in flight and thus is unstable while possessing good lift/dragcharacteristics. Aircraft with this wing shape require stabilizers suchas a tail unit to overcome the pitch down moment as the wing tends tofollow the curve of the meanline 218.

FIG. 14 is a cross section of a preferred wing design 220 with ameanline 222 drawn from the leading side 224 to the rear 226. The wing220 is of a thick design (with a maximum thickness on the order of 30%of chord length) and has a flat horizontal bottom surface 225 duringnormal operation (attitude). In contrast to the conventional meanlineshape of the wing 210 of FIG. 13, the wing 220 of FIG. 14 has aconcave-shaped (upwardly curved) meanline 222. This upwardly curvedmeanline shall be referred to as a reverse or inverted curve of themeanline. In a preferred configuration, the meanline 222 is (a) straightover the rear portion of the wing 220 (e.g., over the rear 70% of thewing) and (b) slightly upwardly curved over the remainder (forward)portion of the wing 220. Alternately, the meanline 222 is upwardlycurved from the C/L forward with the meanline generally straight for thewing portion behind the C/L.

The leading edge 224 of the wing 220 is rounded having a very largeradius R as shown in FIGS. 15-16. Generally speaking, the larger theradius, the more gentle the stall characteristics. In a preferred wingshape with a maximum thickness on the order of 30% of chord length, thenose radius R may be on the order of 6% to 10% of chord length.

With its inverted meanline configuration and large nose radius R, thewing 220 of FIG. 1B has been observed to create a mass of stagnated airpreceding the leading edge 224 of the wing 220. It is postulated thatthe wing 220 assumes an "effective" meanline 223 (an effectiveaerodynamic center) which shifts from straight to downwardly curvedthereby assuming a shape and an angle of attack possessing good liftcharacteristics. Moreover, the wing shape has pitch moments which areself-correcting or stable without requiring an elevator. As the nosedips down, as shown in FIG. 16 the air flow starts to conform to theshape of the meanline raising the nose as the upward curve is followed.The center of pressure C/P is shifted forward creating correctivemoments to return the craft to stable centering position. As the noseturns upward from the normal attitude, the effective meanline 223transitions to being downwardly curved thereby increasing effectivecamber, and air pressure acting on the underside of the rear sectionbehind the center of lift C/L increases (as the section's exposure toair flow is increased) creating normal pitch down corrective moments toreturn the craft to the stable center position.

A conventional wing having a convex curved meanline 218 and small radiusleading edge as shown in FIG. 17 does not exhibit such stability. Such awing only has normal pitch down moments and when forced to an increasedangle of attack, with its small radius leading edge, the air is dividedby the airfoil and air flow stagnation occurs under the wing at muchlower angles of attack. The shift (of the stagnation point) does occurand stagnation builds under the wing such that the air flows forwardlyand vertically over the leading edge causing the stall since the airflow cannot conform to the wing surface. In contrast with a large radiusleading edge as in FIG. 15, the aerodynamic center of the air flowing tothe leading edge shifts relative to the chordline as the angle of therelative wind shifts. This airfoil has "effective camber" achievingstability and equilibrium at various speeds in or out of ground effectand which has good lift characteristics.

The wing 220 is particularly useful at relatively low speeds [on theorder of 25-60 mph (35-90 kph)]or as a ground effect craft, but such aconfiguration may also be suitable or readily modifiable for generalaviation.

The preferred wing design may be incorporated into a variety of flyingcraft designs. FIGS. 18-24 illustrate watercraft 300 which embodies thispreferred wing design. FIG. 18 is a perspective view of the watercraft300 which is a single seat or dual seat ground effects vehicle. Thewatercraft 300 has a single form body structure 310 with left and rightwing sections 340, 350 which blend or merge together to form acontinuous central hull section 320. Essentially the craft 310 comprisesa flying wing structure having the very thick wing cross section on theorder of 30% (maximum wing thickness to chord length ratio) as describedabove.

As best shown in FIG. 20, the watercraft 300 is constructed such thatits mass elements, which include the engine 360 and drive train 374 andpropulsion mechanism (shown as a ducted fan 380 which is comprised ofthe outer duct 381 and rotating fan 379), are distributed to place thecenter of gravity C/G of the craft, without the presence of any pilot orriders, within the vehicle seating area 375. In a preferredconfiguration, the craft's center of gravity is located generallycentrally beneath the seating position of the pilot. The center of liftC/L is also preferably positioned in the same location as C/S.

The desired balance of the craft 300 (to control pitching moment) isachieved by locating the engine forward of the seating position 375 andlocating the radiator 361 and the ducted fan 380 in the rear. The craft300 may be constructed with an inherent stability which permits thepilot to alter the pitch of the craft by moving body position forward orrearward. The weight shift acts against the corrective moments--i.e.increases/decreases air speed trimmed for a given angle of attack. Thepilot straddles the seating area 375 with the pilot's feet beingpermitted to rest on the bottom of the craft 300. The pilot may steerthe craft 300 by leaning to one side or the other in addition to turningthe steering bars 371 which operate the rear dual rudders 382 and 384aft of the ducted fan 380. Though the details of the connection are notshown in this figure, steering bars 371 may be operably connected to therudders 382, 384 by a suitable drive mechanism such as steering cables.Operation of the rudders 382, 384 steer on the water and induce yaw inthe air causing banking turns as the forward end rises due to increasedlift.

Also as in the previous embodiment, fuel consumption is prevented fromdisturbing mass distribution, by positioning the fuel storage tank 377beneath the seating position 375. Therefore, as the fuel in the tank 377is consumed, the weight of fuel remains balanced about the C/G so asmaintain balanced mass distribution about the C/G even as the fuel isconsumed.

Details of the wing shape are illustrated in FIGS. 21-22. FIG. 21 hascross-section lines H-H through L--L which refer to corresponding linesH through L in FIG. 22 illustrating the wing shape at the particularcross-sectional location. As in the previous embodiment, these figuresare drawn to scale to more fully describe the details of the wing shapeof the watercraft 300. As shown in the figures, the leading edge of thebody structure is extremely thick with a substantially horizontal, flatbottom. The wing shape has a maximum thickness (ratio of wing thicknessto chord length) on the order of 30% which is about twice (or more) thatof typical wing designs. The thicker wing generally works better at lowair speeds and the built-in angle of attack relative to the hydrodynamicbottom actually reduces the effective thickness (as to drag). The thickwing also enables the thrust forces to act directly on the center ofgravity and parallel to the hydrodynamic bottom.

The bottom surface is flat to accommodate aquatic planing. In addition,the bottom surface is equipped with hydrodynamic stabilizers 390comprising a series of concavities 392, 393, 394, 395 positioned on theunderside of the central hull section 320. It is intended that theseconcavities 392-395 provide both hydrodynamic stability and increasedlift. The concavities 392-395 provide a pivot to turn on during wateroperation, otherwise the craft would tend to continue to move along astraight line in a crabbing manner. At flying speed, crabbing in the airinduces a bank. The more forward side increases lift, the resultantbanking in air as well as on the surface is favorable to good turningcharacteristics as banking induces the turn.

The bottom surface of the craft 300 is equipped with a step 391 (asshown in FIGS. 20 and 22) such that the forward portion of the craftbottom extends further downward than the rearward portion. Thehydrodynamic bottom portion of the craft 300 is the portion forward ofthe step 391. The craft bottom to the rear of the step 391 provides forlevel flotation when the craft 300 is at rest.

The craft 300 is constructed with a generally flat, horizontal bottomplaning surface. The bottom may have an upwardly curved forward surface.The center of pressure and balance point C/P should be approximately 1/4forward of the aft end of the hydrodynamic portion which is contrary toa symmetrical wing section where the center of lift would be at the 1/4chord position from the leading edge. The craft 300 is preferablydesigned to bring the center of pressure C/p and center of gravity C/G(within allowable variations) to a single point to achieve stability,and when the centers are displaced, to provide corrective moments toreturn to the stable operating position.

The rear of the craft 300 is constructed to form an expanded U-shapedrear section 399 (as the craft is viewed from a rearward location suchas best viewed in FIGS. 18, 19 and 24 and is preferably equipped withvertical stabilizers or fins 396, 398 for added directional stability inthe narrower planforms.

For a typical symmetrical airfoil, the center of lift C/L is located at25% of wing area from the leading edge of the airfoil. In the craft 300,the U-shaped rear section 390 radically shifts the C/L rearward to 32.4%of the wing area (or 41% of the chord length from the leading edge).This rearward shift of the C/L permits the C/G of the craft (andtherefore the seating position of the pilot) to be located at or nearthe center of the vehicle, even if a very lightweight engine 360 isemployed.

A preferred craft may be designed by forming the general overallconfiguration including the reverse camber, U-shaped shaped rear crosssection and an empirically found C/L. Following the 1/4, 3/4distribution around the C/L described above, the bottom surface isconfigured. The meanline with its upward curvature and positive angle ofattack to the flat bottom surface is drawn. The leading edge radius isthen drawn with its center on the meanline and the top surface isprojected equidistant from the meanline. The craft mechanical componentsare then arranged so that C/G, C/L and C/P coincide.

For a single or two person vehicle, the overall dimensions for a sportversion craft may be as follows:

length: 16.0 ft (4.88 m)

8.0 ft (2.44 m)

span: 8.0 ft (1.45 m).

height: 4.75 ft (1.45 m).

Such a vehicle may have a principal hull structure with an aspect ratioon the order of 0.5 as previously described with its wing/body shapehaving a wing thickness to chord length ratio on the order of 30%. Theleft and right wing sections merge with the central hull to form acontinuous wing shape 310 constituting an aerodynamic shape which mayprovide lift over the entire craft surface and not just the wings as inconventional craft.

Other modifications to the design, including the addition ofconventional control surfaces including a tail unit, fins, rudders (suchas on the rear of the vertical stabilizers 396, 398), winglets,ailerons, spoilers, or edge flaps are possible. Nonetheless, a preferredconfiguration as shown in FIGS. 18-24 has no pontoons, ailerons, orsponsons or the like but only a single form wing/body structure.

In its preferred construction, the craft 300 is neutral balanced for astable flight attitude inherent in the structure. The craft wingstructure is by design trimmed for an air speed at a given weight.Adding power (thrust) increases the airflow over the craft wingstructure increasing lift and the vehicle climbs; reducing powersimilarly decreases lift and the vehicle descends. The rate of climb ordescent depends on power. The second control besides power is therudders 382, 384 which provide for turning and/or banking.

When the craft 300 is operating in the air, if the weight (i.e., bymovement of the pilot) is shifted forward, the nose 310 is pitcheddownward and meets aerodynamic forces which pitch the craft 300 back up.These forces can be balanced against each other with a new attitude,reducing the angle of attack. The craft 300 thus becomes balanced ortrimmed for a new higher air speed at the given weight to maintainstraight and level flight.

Similarly, if the weight is shifted rearward, the nose 310 rises,increasing aerodynamic lift and the craft may then be balanced andtrimmed at a new, increased angle of attack and for a slower air speed.

In a sport, lightweight version, the watercraft 300 is capable of flyingin proximity of the water surface with inherent stability and safety.Maneuverability is accomplished by one up/down controller (i.e.,power/throttle) and one right/left controller (i.e., rudders). Theresult is a simple and safe craft with its built-in stabilities.

The craft may be adapted to particular customized configurations. Onerelatively minor reconfiguration is the craft 600 illustrated in FIGS.25-26, FIG. 25 showing a front view and FIG. 26 showing a rear view.Unlike the previous embodiment of watercraft 300 which includes lateralfins 396, 398, the craft 600 is shown as a finless design, but fins maybe added depending on the desired flight characteristics. The craft 600has a single form body structure 610 with left and right wing sections640, 650 which blend or merge together to form a continuous central hullsection 620 to comprise a flying wing structure. The rear of the craft600 is still constructed to form a generally expanded U-shaped rearsection 699, but appears less pronounced due to the absence of fins.

The wing shape of the craft 600 is similar to that of the previousembodiment, however the nose section 620 of the body structure 610 isextremely thick with a substantially horizontal, flat bottom. FIG. 25shows a parting line 615 along the nose section 620. The craft 600includes a hydrodynamic bottom surface which is flat to accommodateaquatic planing. In addition, the bottom surface is equipped withhydrodynamic stabilizers 690 comprising a series of concavities 692,694, 695 positioned on the underside of the central hull. It is notedthat the watercraft 600 has only three concavities which are deeper ascompared to the four shallower concavities 392-395 of the previousembodiment. As compared to the previous embodiment, the craft 600 alsohas a slightly thicker nose section 620 and a slightly greater angle ofattack.

The craft 600 is driven by a ducted fan assembly 680 and steered in partby dual rudders 682 and 684 located behind the fan blade 680. Theremaining details of the craft 600 are similar to the previousembodiment and need not be repeated.

FIG. 27 illustrates a craft 400 according to the embodiments of FIGS.18-26 only on an enlarged scale. The craft 400 is envisioned as acommercial-size transport vehicle powered by a plurality of fans 450,452, 454, 456 (which may alternately be ducted) located in the U-shapedrear section 420 of the craft 400. Left and right vertical stabilizers422, 424 provide additional directional stability for the craft.

FIGS. 28-30 illustrate another embodiment of a craft 500 with a mainbody/wing section 510 and further includes an upper wing 520 having leftand right wing sections 522, 524. The craft 500 is powered by two fanunits 550, 552 located in the U-shaped rear section 520 of the craft500. As shown in FIG. 30, the wing/body section 510 has the flat bottomsurface and cross-sectional wing shape as described above with respectto FIG. 22 for example. The wing sections 522, 524 may also comprisethick wing sections of configuration similar to the central wing/bodysection, but may alternately comprise conventional wing cross sectionalshapes.

The craft 500 may also include a tail section 530 comprising left andright vertical stabilizers 532, 534 to provide additional directionalstability and a horizontal stabilizer 535 to provide additional vehiclepitch control. The craft 500 preferably includes a flat bottom surfaceto accommodate aquatic planing. The bottom surface is equipped withhydrodynamic stabilizers (as in the craft 300 of the previousembodiment) comprising a series of concavities positioned on theunderside of the central hull section 520. It is believed that theseconcavities provide hydrodynamic stability and a pivot point on which toturn during water operation. The concavities are designed to reducecrabbing when the pilot attempts to turn the craft.

While embodiments and applications of this invention have been shown anddescribed, it would be apparent to those skilled in the art that othermodifications are possible without departing from the inventive conceptsherein. The invention, therefore, is not to be restricted except in thespirit of the claims that follow.

What is claimed:
 1. A flying craft having an aerodynamic configuration comprising a central hull section, and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure being constructed and arranged with a meanline which is upwardly curved over a front section thereof.
 2. A flying craft according to claim 1 further comprising a generally horizontal bottom having a hydrodynamic planing surface.
 3. A flying craft according to claim 1 wherein the wing shaped structure has a round leading edge with a nose radius on the order of 6% to 10% of chord length.
 4. A flying craft according to claim 1 wherein the wing shaped structure has a maximum thickness ratio of wing thickness to chord length on the order of 25% to 30%.
 5. A flying craft according to claim 4 wherein the wing shaped structure has a built-in positive angle of attack.
 6. A flying craft according to claim 4 further comprising engine means for powering the craft and propulsion means for applying power from the engine means to propel the craft along a thrustline, the propulsion means being positioned in a rear section of the craft and constructed and arranged to position the thrustline horizontally in alignment with a center of gravity of the craft.
 7. A flying craft according to claim 4 wherein the wing shaped structure has a generally flat bottom planing surface and wherein the wing shaped structure has a thrustline parallel to the flat bottom planing surface.
 8. A flying craft according to claim 4 wherein the wing shaped structure has a generally horizontal bottom forming a hydrodynamic planing surface.
 9. A flying craft according to claim 8 wherein the hydrodynamic planing surface comprises a plurality of longitudinal concavities positioned on an underside thereof.
 10. A flying craft according to claim 8 wherein the wing shaped structure has a thrustline parallel to the horizontal bottom.
 11. A flying craft according to claim 1 wherein the meanline is upwardly curved in a forward 30% of the craft.
 12. A flying craft according to claim 1 wherein the meanline is generally straight over a rear section of the craft.
 13. A flying craft according to claim 1 wherein the meanline is upwardly curved forward of a center of lift of the craft.
 14. A flying craft according to claim 13 wherein the meanline is generally straight rearward of the center of lift.
 15. A flying craft according to claim 1 comprising a ground effects craft, wherein the central hull includes a seating area for a pilot.
 16. A craft according to claim 1 comprising a ground effects craft, wherein the craft includes a single seating area, the seating area accommodating a pilot and a maximum of one passenger in addition thereto, the seating area being longitudinally disposed along a central longitudinal axis of the craft and the passenger being seated behind the pilot.
 17. A flying craft having an aerodynamic configuration comprising a central hull section, a generally U-shaped rear section, and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure being constructed and arranged with a meanline which is upwardly curved over a front section thereof wherein the wing shaped structure has a maximum thickness ratio of wing thickness to chord length on the order of 25% to 30%.
 18. A flying craft having an aerodynamic configuration comprising a central hull section, and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a generally horizontal bottom forming a hydrodynamic planing surface and a built-in positive angle of attack relative to the horizontal bottom.
 19. A flying craft according to claim 18 wherein the wing shaped structure has a maximum thickness ratio of wing thickness to chord length on the order of 25% to 30%.
 20. A flying craft according to claim 19 wherein the wing shaped structure has a round leading edge with a nose radius on the order of 6% to 10% of chord length.
 21. A flying craft according to claim 19 further comprising engine means for powering the craft and propulsion means for applying power from the engine means to propel the craft along a thrustline, the propulsion means being positioned in a rear section of the craft and constructed and arranged to position the thrustline horizontally in alignment with a center of gravity of the craft.
 22. A flying craft according to claim 18 wherein the horizontal bottom is formed with a step such that a forward portion of the bottom surface is lower than a rear portion of the bottom surface.
 23. A flying craft according to claim 18 wherein the hydrodynamic planing surface comprises a plurality longitudinal concavities positioned on an underside thereof.
 24. A flying craft according to claim 18 wherein the wing shaped structure has a thrustline parallel to the horizontal bottom.
 25. A flying craft according to claim 18 further comprising a propulsion system comprising a ducted fan positioned in a rear section of the craft.
 26. A flying craft having an aerodynamic configuration comprising a central hull section, a generally U-shaped rear section, and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a generally horizontal bottom forming a hydrodynamic planing surface and a built-in positive angle of attack relative to the horizontal bottom, wherein the wing shaped structure has a maximum thickness ratio of wing thickness to chord length on the order of 25% to 30%.
 27. A flying craft having an aerodynamic configuration comprising a central hull section, and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a generally horizontal bottom forming a hydrodynamic planing surface and a built-in positive angle of attack relative to the horizontal bottom, wherein the wing shaped structure has a maximum thickness ratio of wing thickness to chord length on the order of 25% to 30%, wherein the central hull includes a seating area for a pilot, the seating area comprising a longitudinally elongated bench seat positioned along a central longitudinal axis of the central hull section for permitting the pilot to adjust body position longitudinally for affecting craft balance.
 28. A flying craft according to claim 27 wherein the craft has a center of gravity located below the elongated bench seat.
 29. A flying craft having an aerodynamic configuration comprising a central hull section, and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a maximum thickness ratio of wing thickness to chord length, wherein the wing shaped structure has a built-in positive angle of attack.
 30. A flying craft according to claim 29 further comprising engine means for powering the craft and propulsion means for applying power from the engine means to propel the craft along a thrustline, the propulsion means being positioned in a rear section of the craft and constructed and arranged to position the thrustline horizontally in alignment with a center of gravity of the craft.
 31. A flying craft according to claim 29 comprising a ground effects craft.
 32. A craft according to claim 29 wherein the maximum thickness ratio of wing thickness to chord length is about 30%.
 33. A flying craft having an aerodynamic configuration comprising a central hull section, and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a maximum thickness ratio of wing thickness to chord length, wherein the wing shaped structure has a generally horizontal bottom and a thrustline parallel to the horizontal bottom.
 34. A flying craft having an aerodynamic configuration, comprising a central hull section, first and second wing sections laterally positioned one on either side central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a maximum thickness ratio of wing thickness to chord length of about 25 to 30%, wherein the wing shaped structure has a generally horizontal flat bottom forming a hydrodynamic planing surface.
 35. A flying craft according to claim 34 wherein the flat bottom comprises a plurality of longitudinal concavities positioned on an underside thereof.
 36. A flying craft according to claim 34 wherein the central hull includes a seating area for a pilot, wherein the craft has a center of gravity positioned on a longitudinal axis below the seating area.
 37. A flying craft having an aerodynamic configuration comprising a central hull section and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a maximum thickness ratio of wing thickness to chord length of about 25 to 30%, wherein the craft has a principal hull structure with an aspect ratio on the order of 0.50.
 38. A flying craft having an aerodynamic configuration comprisinga central hull section, first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a maximum thickness ratio of wing thickness to chord length of about 25 to 30%, and a propulsion system comprising a ducted fan.
 39. A flying craft having an aerodynamic configuration comprisinga central hull section, first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a maximum thickness ratio of wing thickness to chord length of about 25 to 30% and a generally U-shaped rear section as viewed from a rearward location.
 40. A flying craft having an aerodynamic configuration comprisinga central hull section, first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a maximum thickness ratio of wing thickness to chord length of about 25 to 30%, and a longitudinally elongated bench seat for seating a pilot, the elongated bench seat being positioned along a central longitudinal axis of the central hull section for permitting the pilot to adjust body position longitudinally for affecting craft balance during operation.
 41. A flying craft according to claim 40 wherein the craft has a center of gravity located below the elongated bench seat.
 42. A flying craft comprising a craft constructed and arranged without pontoons, ailerons, or sponsons and having an aerodynamic configuration, comprising a central hull section, and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the wing shaped structure having a maximum thickness ratio of wing thickness to chord length of about 25 to 30%.
 43. A craft having an aerodynamic configuration comprising a central hull section and first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure therewith, the first and second wing sections being swept back with the wing shaped structure forming a generally U-shaped rear section as viewed from a rearward location.
 44. A craft according to claim 43 wherein the continuous wing shaped structure comprises a round leading edge with a nose radius on the order of 6% to 10% of chord length and an upwardly curved meanline.
 45. A craft according to claim 43 wherein the continuous wing shaped structure comprises a maximum thickness ratio of wing thickness to chord length of about 30%.
 46. A craft according to claim 43 wherein the craft comprises a flying wing.
 47. A craft having an aerodynamic configuration comprisinga central hull section; first and second wing sections laterally positioned one on either side of the central hull section, the first and second wing sections merging into the central hull section to form a continuous wing shaped structure, the first and second wing sections being swept back with the wing shaped structure forming a generally U-shaped rear section; and a generally horizontal bottom planing surface and a central portion having a plurality of longitudinally aligned concavities positioned on an underside thereof.
 48. A wing structure for a flying craft, comprisinga round leading edge with a nose radius on the order of 6% to 10% of chord length and an upwardly curved meanline.
 49. A wing structure according to claim 48 further comprising a maximum thickness ratio of wing thickness to chord length of about 30%.
 50. A wing structure according to claim 48 further comprising a generally horizontal flat bottom forming a hydrodynamic planing surface.
 51. A wing structure according to claim 50 wherein the flat bottom includes a plurality of concavities positioned on an underside thereof.
 52. A wing structure according to claim 48 further comprising an aspect ratio of about 0.50.
 53. A wing structure according to claim 48 wherein the meanline is upwardly curved forward of a center of lift of the wing structure.
 54. A wing structure according to claim 48 wherein the meanline is generally straight rearward of a center of lift of the wing structure.
 55. A wing structure according to claim 48 wherein the meanline is upwardly curved over a forward portion of the wing structure and wherein the meanline is generally straight over a rear portion of the wing structure.
 56. A wing structure according to claim 48 wherein the wing structure comprises a craft body comprising a flying wing. 